E. Egron

The accretion flow to the intermittent accreting millisecond pulsar, HETE J1900.1−2455, as observed by XMM–Newton and RXTE

We present a study of the accretion flow to the intermittent accreting millisecond pulsar, HETE J1900.1-2455, based on observations performed simultaneously by XMM-Newton and RXTE. The 0.33-50 keV spectrum is described by the sum of a hard Comptonized component originated in an optically thin {\tau}~1 corona, a soft kTin~0.2 keV component interpreted as accretion disc emission, and of disc reflection of the hard component. Two emission features are detected at energies of 0.98(1) and 6.58(7) keV, respectively. The latter is identified as K{\alpha} transition of Fe XXIII-XXV. A simultaneous detection in EPIC-pn, EPIC-MOS2, and RGS spectra favours an astrophysical origin also for the former, which has an energy compatible with Fe-L{\alpha} and helium-like Ne-K{\alpha} transitions. Broadness of the two features suggests a common origin, resulting from reflection in an accretion disc with inclination of (30+4{\deg}), and extending down to Rin=25(+16,-11) gravitational radii from the compact object. However, the strength of the feature at lower energy measured by EPIC-pn cannot be entirely reconciled with the amplitude of the Fe K{\alpha} line, hampering the possibility of describing it in terms of a broad-band reflection model, and preventing a firm identification. Pulsations at the 377.3 Hz spin frequency could not be detected, with an upper limit of 0.4% at 3-{\sigma} c.l. on the fractional amplitude. We interpret the inner disc radius estimated from spectral modelling and the lack of significant detection of coherent X-ray pulsations as an indication of a disc accretion flow truncated by some mechanism connected to the overall evolution of the accretion disc, rather than by the neutron star magnetic field. This is compatible with the extremely close similarity of spectral and temporal properties of this source with respect to other, non pulsing atoll sources in the hard state.

Testing reflection features in 4U 1705−44 with XMM-Newton, BeppoSAX, and RXTE in the hard and soft states

We use data from the bright atoll source 4U 1705−44 taken with XMM-Newton, BeppoSAX, and RXTE both in the hard and in the soft state to perform a self-consistent study of the reflection component in this source. Although the data from these X-ray observatories are not simultaneous, the spectral decomposition is shown to be consistent among the different observations, when the source flux is similar. We have therefore selected observations performed at similar flux levels in the hard and soft states to study the spectral shape in these two states in a broad-band (0.1−200 keV) energy range, with good energy resolution, and using self-consistent reflection models. These reflection models provide a good fit for the X-ray spectrum both in the hard and in the soft state in the whole spectral range. We discuss the differences in the main spectral parameters we find in both states, providing evidence that the inner radius of the optically thick disk slightly recedes in the hard state.

Spectral and timing properties of IGR J00291+5934 during its 2015 outburst

We report on the spectral and timing properties of the accreting millisecond X-ray pulsar IGR J00291+5934 observed by XMM-Newton and NuSTAR during its 2015 outburst. The source is in a hard state dominated at high energies by a comptonization of soft photons (

A relativistic iron emission line from the neutron star low-mass X-ray binary GX3+1

\sim0.9

A complete X-ray spectral coverage of the 2010 May-June outbursts of Circinus X-1

keV) by an electron population with kT

Imaging of SNR IC443 and W44 with the Sardinia Radio Telescope at 1.5 and 7 GHz

_e\sim30

Subarcsecond Location of IGR J17480–2446 with Rossi XTE

keV, and at lower energies by a blackbody component with kT

A TEST of the NATURE of the FE K LINE in the NEUTRON STAR LOW-MASS X-RAY BINARY SERPENS X-1

\sim0.5

The Sardinia Radio Telescope: From a Technological Project to a Radio Observatory

keV. A moderately broad, neutral Fe emission line and four narrow absorption lines are also found. By investigating the pulse phase evolution, we derived the best-fitting orbital solution for the 2015 outburst. Comparing the updated ephemeris with those of the previous outbursts, we set a

A multi-wavelength pipeline for pulsar observations

3\sigma